ZORICA CIVRIC, is an international personality in the area of the spreading and the study of Nikola Tesla's legacy. Electrical engineer of formation, exercised of curator in the Museum Nikola Tesla of Belgrade, for years, she joined the labor constant and deep study of the legacy. Now he is a chief of electrical department and senior curator in the Museum Of the Science and the Technology of Belgrade, continues like it never activates in the tasks of work and investigation. Stands out his global, unitary and humanist approach of the knowledge and the problems of develop worldwide. She is an authoress of numerous books, inexcusable in NT's bibliography and his name is synonymous of rigor, tidiness and merit.We met personally during my visit to Belgrade in 2009.

Nikola Tesla is undoubtedly known as inventor of
rotating magnetic filed and polyphase AC currents. Apart from that, he
contributed by his practical and theoretical works, in the field of generating
and using of high frequency AC currents, in establishing whole range ofnew techniques amongst the most prominent one,
is for sure radio technique.

It is generally accepted that Hertz Heinrich Rudolph
(1857-1894) was the first scientist who worked on trying to invent method and apparatus
for wireless transmission. In 1887 he published experimental proof of Maxwell’s
theory of electromagnetic waves. His work was foundation for future development
of radio.

From the historical point of view development of radio
can be divided in two phases.

In the first phase of development, apparatus based on
Hertz’s apparatus was used. First transmitted messages by radio waves were
impulses grouped in code symbols. Tesla, Marconi, Popov, Slabi, Braun worked on
improvement of Hertz’s apparatuses in the early stage of radio development.

Tesla’s studying of high frequency currents that he
started in 1890 marked second phase in radio development that meant theoretical
and practical improvements. This phase was characterized by application of
continual AC current for wireless transmission and application of resonance
providing possibility of sending and receiving selective messages, increase of
sensitivity of receiver and transmission of continual message.

In his lecture delivered before the American Institute
of Electrical Engineers at Columbia College, N.Y. May 20, 1891 Experiments with Alternate Currents of Very
High Frequency and Their Application to Methods of Artificial Illumination
Tesla announced possibility of practical realization of wireless transmission
of energy.

During 1892 encouraged by success that he had in
London and Paris where he gave lecture the same year about results reached in
the field of high frequency currents, he invented apparatus that has been from
that time part of every radio receiver and transmitter. Apparatus consisted of
“Tesla transformer – Tesla Coil”. From this time term “Tesla Coil” was accepted
in America as well as in Europe.

In his lecture On
Light and Other High Frequency Phenomena delivered before the Franklin Institute,
Philadelphia on February 24, 1893and before
National Electric Light Association St. Louis, on March 1, 1893 Tesla explained
his basic plan of radio technique. Explaining principle that radio receiver
must be tuned to the transmitters frequency, Tesla established basic concept of
complete radio techniques.

In mentioned lecture he was first to give public
explanation of transmitter with continual AC currents for exciting aerial-earth
system as well as explanation of using resonance for effective transmission of
energy between synchronizedtransmitter
and receiver.

In coming years Tesla worked on solving problem of resonance
and resonant circuits and he founded methods of tuning circuits to the defined
frequency by the means of coils of variable inductivity and condensers with
variable capacity.

Till September 1897 Tesla did not file his patents
only in September 2, he field two patent applications that he was granted in
1900. Those patents had the decisive importance in defining priority in radio.

In his patent no. 649.621 Apparatus for Transmission of Electrical Energy that was granted on
February 19, 1900, Tesla defines radio and points outthat the total length of antenna and coil
conductor should beapproximately one
–quarter of the wave length long at the operating frequency.

In his patent no. 645.576 System of Transmission of Electrical Energy granted in March 1900
four tuned circuit system tuned to the same frequency as the system of
receiving and transmitting antenna was protected.

Beside Nikola Tesla, by the end of XIX century, Guglielmo
Marchese Marconi (1874-1937), John Stone (1869-1943) and Sir Oliver Lodge (1851-1940)
intensively worked in the field of radio techniques. In the course of two years
preceding Tesla’s filing of patent application, public attention attracted
Guglielmo Marconi who already in 1895 sent long wave signal at the distance
over one mile long and by this publicly demonstrated radio telegraphy. In 1896 in
England he patented previously shown system. In 1899 Marconi sent a signal over
British Channel and in 1901 he received at Newfoundland signal without wires
that he had sent from his laboratory in Cornwall. Those achievements of
Guglielmo Marconi pushed aside credits of his predecessors and contemporaries
and influenced wider public to assign merits concerning radio to him.

In numerous addressing to the press
Tesla insisted on and asked for his right for inventing radio. Polemics concerning
priority were only topics in the newspapers until 1916 when Marconi Wireless
Telegraphy Company of America in front of the Supreme Court of America filed claim
for damage with explanation that USA during the First World War used wireless
devices and by that infringed Marconi’s patent no. 763.772 of June 28,1904 for improvement in apparatus
for wireless telegraphy.

To be granted this patent Marconi waited
for four years(patent filed in November
10,1900). USA Patent Examiner had been rejecting applicationrecalling on previous state of techniques and
works of Tesla, Lodge, Stone, Braun and Mihailo Pupin. Upon renewal of patent
application, patent was granted in 1904.

In the Court trial lawyers of the
Government of USA disputed request of Marconi Wireless Telegraph Company of
America with justification that used apparatus are based on Tesla’s patents (no.
649.621 and no. 645.576) defining apparatus and system of radio, patent of John
Stone that covered greater selectivity of tuned circuits (no.714.756 of
2.12.1902) and patent of Oliver Dodge providing tuning of variable inductivity (no.
609.154 of 16.8.1989).

Dispute was concluded in October 1943
when the Court definitely disputed priority of Marconi’s patent assigning to Tesla
priority in defining apparatuses comprising of four tuned circuits that
actually present the essential concept that radio transmission is founded on.

Result of this verdict that was
brought after Tesla’s and Marconi’s death haven’t changed to a great extent judgment
of professional public who till today assigns basic concepts of radio to
Marconi. The reason for this could be the fact that the dispute was settled
when the matter of priority was not actual any more. Apart from that, general
attention of the public and media who followed topic of priority was directed
towards Second World War. The Actors of this dispute who could by their
endeavors influence forming of professional opinion hadn’t lived enough for the
verdict.